So many negative comments have been written about people who use hazard lights during the fog. Well, it is true that as per driving rules, it should be used only when the car is parked, but the fact is that using hazard light during fog greatly improves the visibility of the car for those behind. It is very difficult to see cars which do not use hazard light during fog. I personally don't see any hazard in using hazard light in foggy conditions especially if you are driving slow because of the weather. Drivers who notice hazard light should be cautious and the first reaction should be to assess whether the vehicle is parked or slow moving. Of course changing lane with the hazard light on should not be done.